1. Field of the Invention
The present invention relates to a content data delivery system and a method for delivering an encrypted content data, more particularly, to a content data delivery system and a method that delivers a content data to a storage media connected to a handheld device such as a mobile phone.
2. Description of the Related Art
With the recent development of the information society, a content delivery system has become commonly used that delivers to a user terminal a content such as an electronic book, a newspaper, music, a motion picture or the like and makes the content available to the user (see, for example, Japanese application patent laid-open publication No. 2004-350150). The user may use the personal computer connectable to the Internet to access the Internet website for content delivery, and download a content at a cost or at no cost. The personal computer used for the download may itself play the downloaded content data. It is also becoming common to copy the downloaded content data to a handheld device such as a mobile phone terminal or a portable music player and to play the data.
Even when playing the high-quality music on the mobile phone terminal, the current content delivery system cannot download the content data directly to the mobile phone terminal, and instead needs to acquire the content data via the personal computer. It is convenient for the user having no personal computer but only a mobile phone terminal to be able to use the content delivery system only via the mobile phone terminal without using the personal computer. The content delivery provider may also have advantages that more users will use the delivery system and more business opportunities will be created.
Using the content delivery system only via the mobile phone terminal has problems with lower communication speed of the mobile phone network and with more difficult management of the purchased content data. In other words, using the content delivery system via the personal computer may easily manage a large amount of content data using content data management software or the like on the computer. For example, the personal computer may hold and manage a large amount of content data by organizing the data per category, artist, or the like. From the library thus organized, a favorite content data may be transferred to and used on the handheld device of a small storage capacity as appropriate. When the user becomes bored with the transferred content data, the user may copy another favorite content data from the library and play it.
Receiving the content data delivery only via the mobile phone terminal has a problem that it is difficult to appropriately hold and manage a large amount of content data because of the insufficient capacity of the SD memory card used as the storage media and because of the small screen of the display in the handheld device or the like. For a data that has been dissipated or deleted, the relevant content data needs to be purchased again, thereby providing disadvantage and poor economy to the user.